For many decades, the standard means of real-time, long-distance communication has been the telephone. Almost every individual within an organization will have a telephone number which is globally unique and from which they can be reached by any telephone in the world.
In more recent years, calls via IP (Internet Protocol) have been gaining prominence, as they have a number of advantages. Call via IP may be free at the point of use, may offer better audio fidelity using high-quality audio codecs, and may allow video and data sharing as well as simply voice.
Currently, individuals generally provide their contact information in the form of a telephone number, which is short, globally unique, easy to use and works between organizations which have had no previous contact. For IP-media calls, in the following referred to as video calls, several different addressing or number schemes have been developed following the idea of telephone numbers, including but not limited to E.164 (network access number, telephone number, etc.), H.323 IDs (alphanumeric strings representing names, e-mail-like addresses, etc.), and any others defined in Recommendation H.225.0. The video call numbers or video-URIs are unique within a Zone, Domain, among Zones, and among Domains.
Within a network, many IP setups support ways of mitigating the complexity of making an IP media calls, e.g. preconfigured address books on an endpoint let a user call an individual by selecting them from a list. These solutions generally only work within an organization, since they rely on endpoints and servers having the information available to them already, as such they only allow individuals to call users whose details are already in the system.
This becomes problematic when an individual wishes to call a user from a different organization, one whose details are not already known to the individual wishing to make the call.
Norwegian patent application 20092479, the entire contents of which are hereby incorporated by reference, describes a Global Address Database allowing an individual using an IP communication device to contact an individual in an external organization using a single identifier, such as a telephone number, without the caller having any knowledge of the IP capabilities of the called individual. Call servers compatible with this new system will register the range of telephone numbers through which their users can be reached with an address registry or set of registries globally accessible via the Internet.
Another possible solution would be to allow users, individuals and/or organizations, to register their video call numbers with a directory of video call numbers. However, when allowing everyone to register video call numbers with the directory, there is a possibility that someone could register video call numbers that are not a valid address to a real video call endpoint.
Further, many ITSPs (Internet Telephony Service Providers) block video call requests from clients outside the ITSPs domain. In this case, a video call from a first video endpoint outside a ITSPs domain to a second video endpoint inside the ITSPs fails even though the second endpoint has a valid address inside the ITSPs domain. Thus, addresses within an ITSP domain blocking outside video call requests should be considered invalid by a global directory.